Study on Plasma Vitamin K Concentration of Rats Cannulated in Portal and Femoral Veins

Abstract

Fifty μ mol/kg body weight phylloquinone (K₁) and menaquinone-4 (MK-4) were administered perorally to rats cannulated in portal and femoral veins. Two hundred μl of blood was collected from both the veins 0, 1, 3, 5, 10, 15, 30, 60, and 120 min, later. Fifty μl of plasma was used to measurement of vitamin Ks with high performansed liquid chromatography. After the administration of K₁ or MK-4, only the same chemical species of Vitamin K administered were detected during the experiment. After the administration of K₁ and MK-4 mixture, K₁ appeared in plasma from 15 min, MK-4 from 10 min, and MK-4 concentration was significantly higher than that of K₁ from 15 min upto 60 min. There was no difference significant in plasma vitamin K concentrations between portal and femoral veins. The concentration of K₁ at 120 min of the mixed dose was 1.3 times as high as that of single dose. In contrast, the concentration of MK4 at 120 min of the mixture dose was 0.5 times as high as that of single dose. These result suggest that the main absorption route of MK-4 may be an extra-portal pathway, MK-4 is absorbed faster than K₁, and some interactions may be present between K₁ and MK-4.